The present invention relates to a method of folding an air bag which is deployed to protect an occupant in the event of vehicle emergency, and the air bag thereof. More particularly, the present invention relates to a method of folding an air bag which can provide suitable deployment to securely restrain an occupant and which is improved in smooth deployment.
There are various methods generally employed for folding an air bag. FIG. 7 is a sectional view of an air bag for a front passenger (hereinafter, referred to as "passenger air bag") which is folded in one of conventional folding methods. In FIG. 7, right and left side edges 11 of the air bag 1 are folded in bellows. The air bag 1 is folded to have a width corresponding to the width of an air bag case 2 so that the air bag 1 can be accommodated in the air bag case 2.
Also, there is a passenger air bag, which is deployed, at first, toward an upper portion of an instrument panel, and then, extends toward an upper side of an occupant in a front passenger seat.
FIGS. 8(A) and 8(B) show that a passenger air bag which has been folded in a conventional method is being deployed. FIG. 8(A) is a side sectional view, and FIG. 8(B) is a sectional view taken along line 8(B)--8(B) in FIG. 8(A).
Referring to FIGS. 8(A) and 8(B), as an inflator 4 disposed in the air bag case 2 generates gas and the gas enters into the air bag 1 as shown by arrows, an air bag cover 9 arranged on an instrument panel 8 is broken by the inner pressure of the air bag 1, so that the air bag 1 is deployed above the instrument panel 8.
In this state, as shown in FIG. 8(B), an upper portion la of the air bag 1, which is positioned near a windshield glass 3 (hereinafter, referred to as "windshield" or "glass"), strikes the windshield 3 when the upper portion la is still in the folded state.
In the passenger air bag folded in the conventional method, it can not be predicted how the deploying air bag 1 strikes the windshield 3, so that there is a possibility that the glass is subjected to undesired local pressure. In order to prevent undesired local pressure on the glass, various measures have been taken, for example, reducing the output of the inflator, adjusting the mount position of the air bag 1 and/or the angle for mounting the air bag case 2, and increasing the strength of the windshield 3. These measures impair the working efficiency of assembling the passenger air bag and increase the cost.
It is, therefore, desired to provide improved folding methods.
The present invention has been made to solve the above problem, and an object of the invention is to provide a method of folding a passenger air bag, which can provide suitable deployment to securely restrain an occupant and which is improved in smooth deployment.
Another object of the invention is to provide a passenger air bag, which can provide suitable and smooth deployment.
Further objects and advantages of the invention will be apparent from the following description of the invention.